Yes, that was it. I was missing it in my PHP installation. I am very sorry to make a fuss with it here. Necessity of this module for image thumbnails is described in the wiki, I havent read it properly. I am sorry again.

Does anyone know if there is a way to remove the white border / animation around thumbnails if displaying them on a dark background? I cannot seem to find options for this in lightbox settings, or any CSS..